1. Field of the Invention
This invention relates generally to building construction and specifically to the construction of precast composite steel I-beam reinforced concrete panels and the method of interconnecting the precast panels to create floors, roofs and walls in a unitary integrated structure having high wind resistance and increased structural load bearing capabilities.
2. Description of Related Art
The advantages of reinforced concrete has long been known in the building industry, such as higher fire ratings and improved seismic and weather resistance. Concrete walls, floors and roofs have been commonly used in buildings, however pouring on site on forms built onto trusses or joists is slow and labor intensive. Thus, precast concrete building construction panels set into place and joined together to create a structure on site gained acceptance as a method to reduce the time, labor and material costs. The prefabricated panels, however, are not without problems if improperly prepared or installed. Without proper reinforcement or adequate joining of adjacent panels, cracking, questionable structural integrity, and diminished resistance to the forces of nature may result.
Many configurations have been employed utilizing prefabrication of concrete panels to construct buildings; for instance, U.S. Pat. No. 5,987,827 to Lord provides concrete panels formed utilizing a horizontal casting platform and having interlocking abutting joints. The structural integrity of the Lord system is provided wholly by the concrete and embedded reinforcement, requires integral wall panel footing and vibrator compactor for alignment, does not provide for prefabricated roof panels and requires multistory panels to be fabricated in one section thereby rendering the system impractical for off site construction and shipping.
The present invention described herein employs integral steel beams as a column in the wall panels, tilt up alignment adjustability independent of the footing design, continuous welded interpanel connection of steel S-beams forming a structural perimeter joining system, and provides for integral concrete roof panels which can accommodate multistory panel fabrication and transportation without much difficulty.
A precast panel interconnection system relying on concrete keys and keyways and which does not provide for prefabricated roof panels or multistory floor and wall panels is disclosed in U.S. Pat. No. 5,865,001 to Martin. The present invention does not utilize an interlocking panel construction.
U.S. Pat. No. 5,761,862 to Hendershot is a building system utilizing a connector assembly at the end of each panel spanning the vertical section of the panel corrugated edge and extruding steel reinforcement, precast corner sections, tongue and groove roof panel connections, integral precast footings, and structural tensions transmitted primarily by wire mesh and steel reinforcement. The present invention uses embedded steel plates welded panel to panel, even at the corners, the panel edges being beveled with no extruding steel, a continuous S-beam perimeter which accommodates structural tensions and shearing, conventional slab and footing construction, and no tongue and groove roof connection. In addition, the Hendershot system requires a post installation concrete pour while Applicant""s system is wholly constructed on-site from prefabricated components.
U.S. Pat. No. 3,952,471 to Mooney teaches a precast concrete construction system with an integral concrete column structure included in the wall panels, an installation of protruding upright anchor bolts at the time of foundation construction and plates welded across panel joints for inter-panel connections. The present system employs embedded S-beam column members in the wall panels, steel plate embeds or anchor bolts after panel installation and a continuous perimeter S-beam connection.
U.S. Pat. No. 3,724,157 to Miram incorporates complex architecture of removable fasteners and internal steel reinforced panels and plates welded across the panel joints. Miram requires existing structural framework to attach the precast panels to at installation and post installation of steel beams spanning the panel joints. The present invention uses steel S-beams embedded in the wall panels as integral column structures, a continuous perimeter S-beam connection, no pre-installation structure to support the wall panels, and welds plates between panels embeds.
U.S. Pat. No. 4,472,919 to Nourse details a monolithic composite panel construction based on embedded steel channels and does not address the construction of complete structures. The present invention herein is a method of constructing a building utilizing wire mesh reinforced concrete with embedded S-beam columns for use in constructing multi-story buildings interconnecting the same elements for wall, floor and roof components.
In U.S. Pat. No. 5,678,372 to Thompson a system of adjacent reinforced preformed panels are joined to one another at undulating confronting edges wherein alternating reinforcement bars are connected to an arrangement of elongated bars and a zigzag reinforcement bar by a wet knit joint completed by introduction of concrete. Although employable for floors, walls, and roofs like the present invention, the present invention uses welded steel plates to attach the bevel-edged (not alternating steel bar reinforced concave/convex segments) panels together, S-beams embedded in the wall panels as integral column structures, a continuous perimeter S-beam connection, and no concrete poured at time of installation.
A precast building system and method comprising an integrated structural support panel or wall which provides an increase in structural load-bearing capacities and subsequent reduction in structural mobility as compared to existing precast and composite building systems. The resulting structural panels are not limited to use as bearing, retaining, shear and architectural walls, but can be used as floor and roof panels as well. Additionally, regardless of the particular structural application for a which a given panel is applied, the basic design of the composite panel remains the same, which yields improved efficiency in planning, design and construction. The floor panels can be cast with varying degrees of negative camber based on the size of the panel being cast, the element being flipped over after removal from the casting mold to accommodate for the camber so the panel will lay flat when used for a floor surface. The panels can be manufactured as precast or on-site cast, providing maximum efficiency in the logistical implementation of a construction project. Further, the system incorporates the longstanding advantages of precast construction techniques of arbitrary design shapes and rapid assembly while providing the improvement of an I-beam as both a continuous perimeter tie-beam enhancing load reinforcement and providing columnar support, unavailable for instance with a bar joist which would likely collapse when similarly used.
The composite steel beam-to-concrete panel provides for the use of a uniform structural element for all parts of a given structure, expediting the planning and erection phases. The system is manufactured as structural panels on site, or delivered by conventional transportation as precast panels to the construction site. Many of the characteristics of traditional precast panel construction are maintained, however, incorporation of the I-beam within the panel element constitutes a significant structurally advantageous difference in the forming, structural embedding, casting, handling, and erection of the elements as compared to traditional precast construction.
The building system is comprised of a concrete slab of about a 3-inch desired thickness and ranging up to about 50 feet in desired length, featuring an embedded S-shaped steel I-beam, conventional steel wire-mesh, embedded plates, and conventional steel tension reinforcement bars (deformed steel rods). The I-beam provides columnar and flexural support for wall, floor, and roof structures. When used as columnar supports, the embedded I-beams are welded or otherwise anchored to the foundation, and are also welded to the continuous perimeter S-shape I-beam tie beam structure. When employed as flexural members to support roofs or floors, the embedded I-beams are welded to the continuous perimeter S-shape I-beam tie beam structure. Adjacent wall, floor and roof panels are structurally connected with steel weld plates.
According to standard industry practices, a mold or form is constructed according to the panel element dimensions and support requirements. The component reinforcement, including but not limited to S-beam shapes, wire-mesh, tension bars and embed plates are fixed in place. Concrete of standard aggregate and post curing compressive strength, preferably a minimum of 3,000 psi, is poured, allowing sufficient curing time to achieve sufficient strength. The panel is then removed from the mold by a claw-like custom lifting technique, and is ready for transport or on-site erection.
A fundamental feature of the system is the manner in which the composite elements are interconnected to form an integral structure. The columnar element support beams embedded in the panels are welded or otherwise affixed to a transverse steel beam (tie-beam) which forms a continuous perimeter connection structure. The transverse beams can also serve as flexural support for floor and roof elements, e.g., withstanding bending loads imposed by the floor or roof panels, as well as providing structural integrity for wind resistance. In addition to this continuous perimeter flexural and tensile support structure, the columnar elements are rigidly affixed to the supporting foundation. Further, inter-element connections are formed at the panel interfaces to connect panels together, providing additional structural integrity. The resulting structure exhibits superior structural load-bearing characteristics in both compressive and tensile loadings, while providing maximum efficiency in construction expediency and overhead reduction.
The object of the invention is to provide a precast concrete I-beam reinforced panel which, when interconnected using the beams and embedded plates, is interchangeably usable for floors, walls, and roofs to construct a superior structurally load-bearing building which is cost and time efficient and resists most hurricane force winds.
In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.